Harna Karish was a 24th century Tarn individual, an officer in the Tarn Imperial Fleet with the rank of Commander. Karish was a member of the royal Kala circle and was later adopted into the Katula circle.
Karish was several inches taller than Commander William T. Riker's 6'2" height. Karish had the pewter colored tattoo of the Kala clan on his forehead. Karish could speak Federation Standard but found it loathsome.
Karish was assigned by Garu Jord to be a Tarn delegate on the USS Enterprise (NCC-1701-D) as it traveled into the newly opened Tarn Neutral Zone in 2367. While onboard the Enterprise, Karish wore his Dress Uniform and Tarn Ceremonial Blade.
Lieutenant commander Geordi La Forge had described Karish as a "hard case" after the two had a discussion about the Federation-Tarn War and Geordi's ancestry who fought in the American Civil War. Karish later had a discussion with Lieutenant Worf. Both warriors had ancestors who had fought each other at Garamora. When Worf had beamed down to Torgu-Va to prevent Karish from using the third Atomic bomb developed by the Tarn, it had made an impression on Karish. Later the two comrades had returned to the Enterprise-D to consume large quantities of alcohol.
When the Enterprise had discovered the Tarn and Human descendents on Torgu-Va, Karish had originally protested any involvement by the Federation, claiming that the planet's inhabitants should be under the protection of the Prime Directive. When Lieutenant Commander Data cited historical examples showing how the Prime Directive would not be applicable on Torgu-Va, Karish agreed to beam down to the surface and talk with the Tarns. There he had met Gadin and after much discussion, joined them in battle. Eventually Gadin's circle, Katula, had adopted Karish into their clan. Upon Gadin's death, Karish took command. When faced with mutual destruction, Karish agreed to the cease-fire. With the hostilities ended, Karish agreed to stay and help with the rebuilding.
Karish enjoyed drinking Hammasi and was very surprised to find it available on the Enterprise. Karish also had an appreciation for Qiva, a Tarn historical figure from the Federation-Tarn War. (TNG novel: The Forgotten War)